Do Solar Panels Work on Cloudy Days? The Truth About UK Weather and Solar Power

One of the most common questions people ask is: will solar panels work when it is cloudy?

This is a fair worry. The UK is known for its cloudy skies and rainy days. But the good news is that solar panels do still work in these conditions, just not at full power.

In this post, we will explain how solar panels make energy even when the sun is not shining and how you can still save money with solar in cloudy places.

How Solar Panels Work on Cloudy Days

Solar panels use light, not heat, to make electricity. That means even on a grey day, when you cannot see the sun, some light is still getting through the clouds.

On a cloudy day, your panels may make 10 to 25 percent of the energy they would on a sunny day. This is called reduced output, and it happens because thick clouds block some sunlight.

The University of Sheffield runs a live solar data tracker. It shows that even in winter, panels across the UK are still producing power.

If you want to know what solar can do when the sun is shining, read our post: Can Solar Panels Really Power a Whole House in the UK?

How Much Energy Can You Expect?

The amount your system makes on a cloudy day depends on:

• The time of year (days are shorter in winter)

• The type and angle of your roof

• The size and quality of your solar panels

Even though output drops in cloudy weather, most homes still make enough power to cut their energy bills, especially in spring and summer.

The Energy Saving Trust says a typical system in the south of England can make around 3,000 kilowatt hours a year. That is about 80 percent of what a family home might use.

Is Solar Still Worth It in Cloudy Areas?

Yes, absolutely. In fact, Germany, which has even less sunshine than parts of the UK, is a world leader in solar power.

What matters most is your yearly total power generation, not just what happens on one grey day. Your panels will do more in summer and less in winter, but over the year, it balances out.

How to Get the Most Out of Solar in Cloudy Weather

To make the most of your solar panels even when the sun is hiding:

• Use a solar battery to store power for use in the evening

• Run high-use appliances like washing machines during daylight hours

• Keep your panels clean and free from dirt

• Choose a trusted installer who will design the system well

To keep birds from nesting under panels and causing problems, see our Bird Proofing Guide.

Final Thoughts

Solar panels do not stop working just because it is cloudy. They still make power — and over the course of a year, most homes in the UK can benefit from solar.

If you want to know how well solar could work for your roof, get a tailored solar quote from Solarsmith today. It is quick and there is no pressure.